From 40413955ee265a5e42f710940ec78f5450d49149 Mon Sep 17 00:00:00 2001 From: "yujuan.qi" Date: Mon, 31 Jul 2017 11:23:01 +0800 Subject: [PATCH] Cipso: cipso_v4_optptr enter infinite loop in for(),if((optlen > 0) && (optptr[1] == 0)), enter infinite loop. Test: receive a packet which the ip length > 20 and the first byte of ip option is 0, produce this issue CVE: CVE-2018-10938 Upstream-Status: Backport Signed-off-by: yujuan.qi Acked-by: Paul Moore Signed-off-by: David S. Miller Signed-off-by: Andreas Wellving --- net/ipv4/cipso_ipv4.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c index c4c6e19..2ae8f54 100644 --- a/net/ipv4/cipso_ipv4.c +++ b/net/ipv4/cipso_ipv4.c @@ -1523,9 +1523,17 @@ unsigned char *cipso_v4_optptr(const struct sk_buff *skb) int taglen; for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) { - if (optptr[0] == IPOPT_CIPSO) + switch (optptr[0]) { + case IPOPT_CIPSO: return optptr; - taglen = optptr[1]; + case IPOPT_END: + return NULL; + case IPOPT_NOOP: + taglen = 1; + break; + default: + taglen = optptr[1]; + } optlen -= taglen; optptr += taglen; } -- 2.7.4